US1784135A - Floor covering - Google Patents

Description

Patented 9, 1930 UNITED STATES PATENT OFFICE CABLE'I'ON ELLIS, OI" KONTCLAIB, NEW JERSEY, ASSIGNOR TO ELLIS-FOSTER COM- PANY, A CORPORATION OF NEW JERSEY FLOOR COVERING Ho Drawing. Application filed February 26, 1927, Serial No. 171,380. Renewed February 8, 1930.

This invention relates to floor coverings and particularly to floor coverings composed of a substratum of saturated felt or other appropriate backing, cushioning or supporting material carrying a tread veneer containing nitrocellulose bodies.

More specifically the invention relates to a duplex floor covering or floor rug consisting of a saturated felt base and a tread veneer containing nitrocellulose and a resinous body, preferably a resin of the glyceride type, that is, a resin in which glycerol has been employed to bring about reaction with other substances and thereby either create resins or 175 modify natural resins.

In addition to a base or backing of asphalt saturated felt, other backing such as plain or waterproof paper, cloth, burlap, and the like, may likewise be employed as the supporting mediumsfor the nitrocellulose plastic composition. Instead of being applied asa sheet of continuous veneer, the tread composition may be a plied in small metrical esigns and in di erent colors so as 5 to obtain an inlaid effect.

The felt base employed, ifof the saturated type, preferably should be free from oily substances and exudations which would preclude satisfactory adhesion .of the tread composition. Roofing paper, for example, often is very oily. A better type of material for the purpose is the saturated felt now employed in making cheap floor coverings by printing a design on the surface with printing paint.

Saturated felt of this type is inost satisfactory for the purpose. The under side of such saturated felt may be finished with a coating of a hard wax, as, for example, Montan'wax containing some red pigment. This prevents 40 the asphaltic material of the'saturated felt from coming in direct contact with the floor and in addition gives a satisfactory finish to 'the under side. 4 A plastic composition is obtained by dissolving nitrocellulose, resin and plasticizing ieces cut in geoency on drying to show curling at the corners or edges. Since this contraction is upward, a floor rug of this character would not be satisfactory with upturned edges which would be likely to catch the foot. On the other hand, nitrocellulose of quite, low viscosity, such for example, as that lgnown as one-half second, although requiring considerably less solvent forms a less tough veneer. Nitrocellulose of a viscosity ranging from four to fifteen seconds, based on the usual measurements employed in lacquer determinations, may be ad- 7 vantageously employed and preferably a grade of celluloid nitrocellulose of twentyfive to thirty second viscosity is useful.

In dissolving nitrocellulose of low viscosity the higher boiling solvents such as butyl 7 acetate, amyl acetate, and the like, or mixtures of esters of this general character with hydrocarbons such as xylol or solvent naphtha may be employed as the vollime of solvent to be eliminated on drying will not be excessive. VVithincreasing viscosities more solvent of this character is required and therefore when employing nitrocellulose of twenty-five second viscosity or higher I preferably employ a highly volatile solvent in which nitrocellulose dissolves with great readiness and without producing'the high viscosity characteristic of some other and higher boiling solvents. Among such low boiling powerful solvents, acetone is pre- 90 eminent. In itnitrocelluloseof high viscosit in other solvents dissolves readily to a muc thinner composition. Volatile hydrocarbonssuch as benzol may be added to cheapen the mixture. Since such highly volatile solvents are liable to evaporatetoo rapidly during handling and when coating, preferably I add to such compositions a small amount of a wax such as paraflin or ceresin wax as the presence of the wax in the coating mixture delays evaporation at room temperature, never-' theless, the solvent may be quickly expelled on heating say twenty to thirty degrees above room temperature. Ordinarily onl two to five per cent of wax, based on the ve icle employed, is required, and this constitutes therefore only a very small per cent of the total composition. I have observed that the presence of this small amount of wax is not inimical to the formation of a tread veneer of good strength.

\Vhile I have specified in particular such highly volatile solvents for dissolving nitrocellulose of high viscosity, it should be understood that I may likewise use higher boiling solvents in this manner, with or without wax, or may employ mixtures of low boiling and high boiling solvents.

In some cases water dispersions of nitrocellulose and the associated fixed materials employed in the binding component may be availed of in order to avoid the use of volatile organic solvents. Thus, a mixture of nitro-' cellulose, resin and plasticizer may be incorporated with a small amount of bentonite or other dispersing agent, water added and the mixture thoroughly agitated in a owerful stirring device such as a Werner fieiderer mixer until a uniform dispersion results. In the preparation of such a dispersion the addition of a small amount of volatile solvent is not precluded. Such a solvent may be of the amyl acetate type and therefore not miscible with water, or it may be of, for example, theacetone type and therefore miscible with water so that on the addition of water to the bentonite-containing mixture the intermingling of the water and the watersoluble solvent assists in the emulsification or dispersion.

Various plasticizing agents may be .employed'with the nitrocellulose to confer flexibility. A considerable proportion of such plasticizer is required in order to obtain the proper feel or liability of the floor covering. Such a pr uct must remain flat on the floor or be self-flattening. A plasticizer of the type of tricresyl phosphate is useful to reduce the inflammability of the nitrocellulose and may be used in some cases. For tread veneer which is white or nearly white containing, for example, zinc oxide as the pigment, tricresyl phosphate is liable to discoloration, especially when sunlight falls on the surface of the floor covering. Tricresyl phosphate also is somewhat more expensive than certain other plasticizers. Provided that suitable fire resistance can bev obtained in other ways, it is frequently desirable to use certain other plasticizers such as dibutyl phthalate or diamyl phthalate. Castor oil, blown castor oil,

, blown rape oil, and the like, also may be employed, especially in conjunction with an effective plasticizer such as dibutyl phthalate.

In the present invention in its preferred form a plasticizer of the type of tricresyl of fillers having water 0 hydration, for ex-- ample, calcium sulphate or gypsum, which contains water of constitution. This is readily evolved when a strong igniting heat is applied. Plaster of Paris wet with water and then'dried and ground is especially efficient in this respect. The present invention contemplates the employment specifically of hydrated calcium sulphate as a fire resisting material in conjunction with readily combustible plasticizers such dibutyl phthalate. Another substance assisting in suppressing combustion is magnesium carbonate. This may be employed as the finely-ground mineral or it may be employed as the precipitated so-called light magnesium carbonate. A cheap form is ground dolomite. In addition to giving off carbon dioxide quite readily (at a temperature below 300 C.) the light magnesium-carbonate serves as an antacid material to neutralize any nitrous products evolved in the course of time from the nitrocellulose. A mixture of hydrated calcium sulphate and magnesium carbonate may be employed advantageously, supplying a filler which coo rates not only as an antacid, but also as a re resisting agent or reagent.

While in some forms of the present invention I may omit resinous substances entirely, I prefer, 1n most cases, to employ some resin to secure a hardening effect or other modification of physical properties. If plasticizer is employed sufiicient in amount to afford a high degree of pliability, the tread veneer may prove to be too soft and easily abraded. The addition of resin corrects this condition. Various natural resins such as rosin, dammar, manila and Pontianak resins, balsam resins, fir-tree resin, and the like, may be employed, but as a. rule such resins in the raw state do not possess the requisite physical properties, nor dothey blend to good advantage with the nitrocellulose, or their solubilities may be inappropriate. Resins which have been chemically modified, as, for example, natural resins of an acid character treated with glycerol to form glyceride resins are more advantageous for the purpose. This includes ester gum or rosin ester and various esterified copals. Still better results are derived by esterifying rosin and a crystalline organic acid such as phthalic acid with glycerol to produce a resinous complex, namely; rosin phthalic glyceride resin. The introduction of the phthalic radical affords a greater blending with the nitrocellulose, more akin to the phthalic esters, e. g., dibutyl phthalate. In additions to such artificial resins of the glyceride type, I may also employ a series of resins which I term rotective resins, prepared from organic acids and glycerol, resins of this eneral character being set forth in Serial 0. 142,532. Glyceride resins thus made from phthalic or other crystalline organic acid or anhydride and a higher fatt acid such as those derived from cottonsee linseed, rapeseed, soya bean, peanut, lard and other oils are more enduring with nitrocellulose than those glyceride resins which contain a natural resin such as rosin in combination. However, the presentinvention embraces the employment of chemically modified or artificial resins and synthetic resins of the glyceride type and also others compatible with nitrocellulose for the purposes herein set forth.

In my copending application Serial No. 148,112 I have used the term modified resins applying to hardened rosin, rosin ester, or ester gum, and the like. In said application, as already stated, the employment of a cooperating fillersuch as hydrated calcium sulphate also has been disclosed. Specific features of the present application are derived from said application Serial No. 148,112 with respect to t-heuse in tread veneer of nitrocellulose, a modified resin such as ester gum and a cooperating filler of the hydrated calcium sulphate type.

As stated in Serial No. 144,647 organic fillers such as ground cork, wood flour, and the like, may be incorporated with'nitrocellulose and glyceride resins in the production of fioor coverings or linoleum products.

' Some of the glyceride resins, especially those particularly described in Serial No. 144,647 and'specifically cottonseed phthalic glyceride resins may be'used in some cases without nitrocellulose.

A desirable method of procedure is to dissolve the nitrocellulose in a portion of the solvent employed, the remainder of such solvent being employed to dissolve the rosin ester or other glyceride ester used. Softeners and plasticizers are added and the two solutions mixed. Care should be taken that the nitrocellulose is thoroughly dissolved so as to be entirely free from lumpiness. The fire resisting filler such as gypsum, is added indicated, various means may be employed to carry through the final mixing to complete uniformity after the composition has been incorporated in the Werner Pfieiderer machine. The composition then may be carried by a suitable conveyor to sheeting rolls where it is deposited in ahopper over the sheeting machine and the composition distributed over a' web of saturated felt passing through the rolls. The latter preferably should be differential, that is, one roll revolving faster than the other. In some cases a spreading roll may be first employed followedby a smoothing roll.

If solvents of the high boiling type have been employed in the plastic composition drying will take a considerable period of time and may be carried .out by conveying the sheeted web into a festooning chamber where it is suspended on rollers and is allowed to dry at a temperature of say, 130 to 140 F. Drying will require from 5 to 15 hours as a rule and whenthe solvent has evaporated completely or nearly to completion so that the surface is hard and the web can be handled without dama c, it may be wound upon a roll and then ed through a calendar roll which is preferably hot.

In the operation of the various rolls it is desirable to have a ground connection in order to avoid the accumulation of static electricity.

The plastic mixture is usually of a stiff putty-like consistency capable of spreading between the rolls to sheet out into a uniform smooth thin tread veneer on the saturated felt. The presence of a small amount of wax appears to improve the spreading qualities of the composition and furthermore when the coating is dry the presence of the wax apparently aids in the burnishing or polishing efl'ect obtainable by hot rolling, as set forth in Serial No. 152,310. Hard polishing waxes such as carnauba or Montan wax may be included in the composition to obtain a greater burnishing effect.

When the solvent is of the highly volatile type such as a mixture of acetone and benzol with possiblythe addition of a few per cent of a nitrocellulose solvent havingv a higher boiling point, e. g., butyl acetate, the drying may be carried out quite readily by passing through a drying oven instead of using the festooning drier.

A formula involvin the employment of a glyceride resin of t e rosin ester species is as follows, the proportions given being by weight:

25 second viscosity nitrocellulose 40 Rosin ester 4O Tricresyl phosphate 40 Castor oil 40 Ground cork passing mesh 100 Powdered gypsum 300 Pigment 10 Wax 2 Ethyl acetate 35 Benzol 48 Butyl acetate 15 Another formula containing solvents of a higher boiling point is the following:

A formula containing a glyceride resin still further chemically modified and involving the use of dibutyl phthalate as a plasticizing agent is the following;

Rosin phthalic glyceride resin 40 25 second viscosity nitrocellulose 40 Dibutyl phthalate 75 Ground cork 100 Hydrated calcium sulphate 300 Pi ment 1O Solvent", 100

The rosin phthalic glyceride resin employed in this formula was made by heating a mixture of Rosin 100 Phthalic anhydride 50 Glycerol 48 to a temperature gradually approximating 290 C. The reaction was carried out in an aluminum reaction vesselprovided with an agitator. The resin thus used was hard and somewhat brittle having an acid number of from 10 to 12.

The solvent employed in the last mentioned formula may be the same as used in either the first or second formula set forth.

The plastic material thus prepared is sheeted onto a saturated felt base in the manner described above.

In the foregoing formulae, it will be noted that the amount of plasticizer emplo ed is approximately equal to the amount 0 resin and nitrocellulose combined. In some cases larger or smaller percentages of resin may be employed. The resin tends to enhance the bonding action of the fillers employed permitting the use of less nitrocellulose than would otherwise be needed. The resins also exert a noticeable hardening action on the tread veneer without decreasing the flexibility to any material'extent. Thus, curling is overcome without sacrifice of hardness and resistance to wear.

The tread veneer may be applied in different colors to get a mottled effect as set forth in Serial No. 152,520. Such j asp effects may be further treated by printing a border in an appropriate pattern on the veneer surface. This printing may be done with ordinary print paint or a printing composition may be made with a nitrocellulose binder. This procedure may be carried out in accordance with the disclosure of my copending application Serial No. 148,112. The veneer surface, whether made in plain colors or polychrome, with or without printed border, may, if desired, be lacquered with a nitrocellulose lacquer material.

In the foregoing I have referred to a tread veneer, by which term I refer to a coating of plastic material applied as, for example, in the manner aforesaid to produce a layer which preferably is substantially thinner than the saturated felt which supports it. Thus, on a saturated felt 1 m. m. in thickness I may apply a tread veneer m. m. in thickness, giving a ratio of 3: 1 thickness of saturated felt to tread veneer. In general, I prefer to maintain approximately this ratio,

although thicker or thinner tread veneers may be used in some cases.

One form of the invention is related to that set forth in my copending application Serial No. 152,520 concerning the. treatment, for shipment, of the rugs, runners or other forms of floor covering made hereunder. To prepare for transportation the floor covering preferably is rolled compactly so that the tread veneer faces outwardly, while the saturated felt backing is on-the inside; that is, a cross section of the roll shows the tread of each convolution facing outwardly, while the back of the saturated felt is facing inwardly. By rolling in this manner the tread veneer is maintained in a state of extension, 0. condition which is highly desirable. Rolling such floor coverings reversed, that is with the tread facing inwardly, would place the tread surface under compression and would tend to favor shrinkage of the veneer. Hence, one

the foregoing, said roll having the tread veneer facing outwardly, whereby the tread veneer is maintained relatively in a state of extension.

Finally, it may be stated that in addition to the components set forth in an illustrative manner by the fore-going formula, other equivalent substances may be employed and also various additions of diverse substances may be introduced to modify the character of the composition in one way or another,

'such additions including various natural resins, and also artificial and synthetic resins, including coumarin resin, phenol aldehyde resins, zinc butyl phthalate resin and the like. Various antacid matters such as amines or other organic neutralizing agents may be included in the above formulae, as also mineral and acid agents such as calcium or magnesium carbonate, zinc oxide, and the like. The zinc oxide serves both as a pigment and as an antacid agent. Magnesium carbonate 1 serves as afiller, fire-retarding substance, and an acid material.

What I claim is 1. A fioor covering in transportable form 8. A floor covering comprising a saturated felt web having adherent thereto a tread veneer containing nitrocellulose, a synthetlc glyceride resin, a natural resin glyceride, and

a fire-retarding mineral substance.

9. A floor covering comprising a backing of asphalt-saturated felt substantially free from oil, coated with a nitrocellulose layer carrying a filler comprising an antacid, a combustion-retarding pigment and an .inert filling component.

10'. A floor covering comprising a backing, carrying a coating of nitrocellulose containing a synthetic resin, a plasticizer, and a filler comprising an antacid, a combustionretarding pigment, and an inertfilling component, said nitrocellulose coating being finished with a nitrocellulose-synthetic resin composition.

CARLETON ELLIS.

comprising a roll of saturated felt web carrying in a state of extension an adherent tread veneer contalnlng nitrocellulose, a glycerlde resin, and a finely-divided fire-retarding.

felt web having adherent thereto a tread veneer containing nitrocellulose, a glyceride resin, and a finely-divided fire-retarding mineral substance, the underside of the web being finished with a coating of a hard wax.

6. A floor covering comprising a saturated felt web having adherent thereto a tread veneer containing nitrocellulose, a glyceride resin, and a finelyedivided fire-retarding mineral'substance, and a small amount of wax.

7 A floor covering comprising a saturated felt web having adherent thereto a tread veneer containing nitrocellulose, a glyceride resin, and mineral substances yielding combustion suppressing gases attemperatures ranging around the ignition points of the combustible constituents of the composition.